The Collaborative International Dictionary of English v.0.48:

Teguexin \Te*guex"in\, n. (Zool.)
   A large South American lizard (Tejus teguexin). It becomes
   three or four feet long, and is blackish above, marked with
   yellowish spots of various sizes. It feeds upon fruits,
   insects, reptiles, young birds, and birds' eggs. The closely
   allied species Tejus rufescens is called red teguexin.
   [1913 Webster]